Method and device for performing cooling-or cryo-therapies for, e.g., angioplasty with reduced restenosis or pulmonary vein cell necrosis to inhibit atrial fibrillation

ABSTRACT

The present invention provides an enhanced method and device to inhibit or reduce the rate of restenosis following angioplasty or stent placement. The invention involves placing a balloon tipped catheter in the area treated or opened through balloon angioplasty immediately following angioplasty. The balloon, which can have a dual balloon structure, may be delivered through a guiding catheter and over a guidewire already in place from a balloon angioplasty. A fluid such as a perfluorocarbon may be flowed into the balloon to freeze the tissue adjacent the balloon, this cooling being associated with reduction of restenosis. The catheter may also be used to reduce atrial fibrillation by inserting and inflating the balloon such that an exterior surface of the balloon is in contact with at least a partial circumference of the portion of the pulmonary vein adjacent the left atrium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/039,466, filed Jan. 3, 2002 entitled “Method and Device forPerforming Cooling- or Cryo-Therapies for, e.g., Angioplasty withReduced Restenosis or Pulmonary Vein Cell Necrosis to Inhibit AtrialFibrillation”, which is a divisional of U.S. patent application Ser. No.09/516,319, filed Mar. 1, 2000, entitled “Method and Device forPerforming Cooling- or Cryo-Therapies for, e.g., Angioplasty withReduced Restenosis or Pulmonary Vein Cell Necrosis to Inhibit AtrialFibrillation”, now abandoned, which is a continuation-in-part of U.S.patent application Ser. No. 09/052,545, filed Mar. 31, 1998, entitled“Circulating Fluid Hypothermia Method and Apparatus”, now U.S. Pat. No.6,231,595, and a continuation-in-part of U.S. patent application Ser.No. 09/215,038, filed Dec. 16, 1998, entitled “Inflatable Catheter forSelective Organ Heating and Cooling and Method of Using the Same”, nowU.S. Pat. No. 6,261,312.

CROSS-REFERENCE TO MICROFICHE APPENDIX

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BACKGROUND OF THE INVENTION

Balloon angioplasty, or the technology of reshaping of a blood vesselfor the purpose of establishing vessel patency using a balloon tippedcatheter, has been known since the late 1970's. The procedure involvesthe use of a balloon catheter which is guided by means of a guidewirethrough a guiding catheter to the target lesion or vessel blockage. Theballoon typically is equipped with one or more marker bands that allowsthe interventionalist to visualize the position of the balloon inreference to the lesion with the aid of fluoroscopy. Once in place,i.e., centered with the lesion, the balloon is inflated with abiocompatible fluid, and pressurized to the appropriate pressure toallow the vessel to open.

Typical procedures are completed with balloon inflation pressuresbetween 8 and 12 atmospheres. A percentage of lesions, typically heavilycalcified lesions, require much higher balloon inflation pressures,e.g., upward of 20 atmospheres. At times, the balloon inflationprocedure is repeated several times before the lesion or blockage willyield. The placement of stents after angioplasty has become popular asit reduces the rate of restenosis.

Restenosis refers to the renarrowing of the vascular lumen followingvascular intervention such as a balloon angioplasty procedure or stentinsertion. Restenosis is clinically defined as a greater than 50% lossof initial lumen diameter. The mechanism or root causes of restenosisare still not fully understood. The causes are multifactoral, and arepartly the result of the injury caused by the balloon angioplastyprocedure and stent placement. With the advent of stents, restenosisrates have dropped from over 30% to 10-20%. Recently, the use andeffectiveness of low-dose radiation administered intravascularlyfollowing angioplasty is being evaluated as a method to alter the DNA orRNA of an affected vessel's cells in the hope of reducing cellproliferation.

Besides restenosis, another cardiological malady is atrial fibrillation.Atrial fibrillation refers to very rapid irregular contractions of theatria of the heart resulting in a lack of synchronization between theheartbeat and the pulse. The irregular contractions are due to irregularelectrical activity that originates in the area of the pulmonary veins.A proposed device, currently under development, for treating atrialfibrillation is a balloon filled with saline that can be ultrasonicallyagitated and heated. This device is inserted in the femoral vein andsnaked into the right atrium. The device is then poked through theinteratrial septum and into the left atrium, where it is then angledinto the volume adjoining the suspect pulmonary vein with the leftatrium.

Research in atrial fibrillation indicates that substantially completecircumferential necrosis is required for a therapeutic benefit. Theabove technique is disadvantageous in that circumferential portions ofthe tissue, desired to be necrosed, are not in fact affected. Othertechniques, including RF ablation, are similarly inefficient. Moreover,these techniques leave the necrosed portions with jagged edges, i.e.,there is poor demarcation between the healthy and the necrosed tissue.These edges can then cause electrical short circuits, and associatedelectrical irregularities, due to the high electric fields associatedwith jagged edges of a conductive medium.

The above technique is also disadvantageous in that heating is employed.Heating is associated with several problems, including increasedcoagulum and thrombus formation, leading to emboli. Heating alsostimulates stenosis of the vein. Finally, since tissues can only safelybe heated to temperatures of less than or about 75° C.-85° C. due tocharring and tissue rupture secondary to steam formation. The thermalgradient thus induced is fairly minimal, leading to a limited heattransfer. Moreover, since heating causes tissues to become less adherentto the adjacent heat transfer element, the tissue contact with the heattransfer element is also reduced, further decreasing the heat transfer.

SUMMARY OF THE INVENTION

The present invention provides an enhanced method and device to inhibitor reduce the rate of restenosis following angioplasty or stentplacement. The invention is similar to placing an ice pack on a sore oroverstrained muscle for a period of time to minimize or inhibit thebio-chemical events responsible for an associated inflammatory response.An embodiment of the invention generally involves placing aballoon-tipped catheter in the area treated or opened through balloonangioplasty immediately following angioplasty. A so-called “cryoplasty”balloon, which can have a dual balloon structure, may be deliveredthrough a guiding catheter and over a guidewire already in place from aballoon angioplasty. The dual balloon structure has benefits describedbelow and also allows for a more robust design, providing significantsafety advantages to the patient because two balloons must be broken ifcooling fluid is to deleteriously infuse into the patient.

The dual balloon may be centered in the recently opened vessel with theaid of radio opaque marker bands, indicating the “working length” of theballoon. In choosing a working length, it is important to note thattypical lesions may have a size on the order of 2-3 cm. A biocompatibleheat transfer fluid, which may contain contrast media, may be infusedthrough the space between the dual balloons. While this fluid does notcirculate in this embodiment, once it is chilled or even frozen bythermal contact with a cooling fluid, it will stay sufficiently cold fortherapeutic purposes. Subsequently, a biocompatible cooling fluid with atemperature between about, e.g., −40° C. and −60° C., may be injectedinto the interior of the inner balloon, and circulated through a supplylumen and a return lumen. The fluid exits the supply lumen through askive in the lumen, and returns to the refrigeration unit via anotherskive and the return lumen.

The biocompatible cooling fluid chills the biocompatible heat transferfluid between the dual balloons to a therapeutic temperature betweenabout, e.g., 0° C. and −50° C. The chilled heat transfer fluid betweenthe dual balloons transfers thermal energy through the balloon wall andinto the adjacent intimal vascular tissue for the appropriatetherapeutic length of time. Upon completion of the therapy, thecirculation of the biocompatible cooling fluid is stopped, and the heattransfer fluid between the dual balloons withdrawn through the annularspace. Both balloons may be collapsed by means of causing a soft vacuumin the lumens. Once collapsed, the cryoplasty catheter may be withdrawnfrom the treated site and patient through the guiding catheter.

In more detail, in one aspect, the invention is directed to a device totreat tissue, including an outer tube, an inner tube disposed at leastpartially within the outer tube, and a dual balloon including an innerballoon and an outer balloon, the inner balloon coupled to the innertube at a proximal and at a distal end, the outer balloon coupled to theinner tube at a distal end and to the outer tube at a proximal end. Afirst interior volume is defined between the outer balloon and the innerballoon in fluid communication with an inlet in the volume between theouter tube and the inner tube.

Variations of the invention may include one or more of the following.The inner tube may further define a guidewire lumen, a supply lumen, andreturn lumen. The supply lumen may define a hole or skive such that afluid flowing in the supply lumen may be caused to flow into a volumedefined by the inner balloon, and the return lumen may define a hole orskive such that a fluid flowing in a volume defined by the inner balloonmay be caused to flow into the return lumen. The guidewire lumen mayextend from a proximal end of the inner tube to a distal end of theinner tube. The device may further comprise at least two radiallyextending tabs disposed around a circumference of the inner tube tosubstantially center the inner tube within the dual balloon. The devicemay further comprise at least one marker band disposed on the inner tubeto locate a working region of the device at a desired location. Thedevice may further comprise a source of chilled fluid having a supplytube and a return tube, the supply tube coupled in fluid communicationto the supply lumen and the return tube coupled in fluid communicationto the return lumen. A source of fluid may also be included, the sourceof fluid coupled in fluid communication to a volume between the innerballoon and the outer balloon. The fluid may be a perfluorocarbon suchas Galden fluid. The fluid may also include contrast media.

In another aspect, the invention is directed to a method of reducingrestenosis after angioplasty in a blood vessel. The method includesinserting a catheter into a blood vessel, the catheter having a balloon.The balloon is then inflated with a perfluorocarbon such that anexterior surface of the balloon is in contact with at least a partialinner perimeter of the blood vessel, the perfluorocarbon having atemperature in the range of about −10° C. to −50° C.

Variations of the method may include one or more of the following. Themethod may include disposing the catheter at a desired location using atleast one radio opaque marker band. The method may include flowing theperfluorocarbon into the balloon using a supply lumen and exhausting theperfluorocarbon from the balloon using a return lumen. The balloon maybe a dual balloon, and the method may further include providing a heattransfer fluid in the volume between the dual balloons. The heattransfer fluid may include a contrast media fluid. The method mayinclude disposing the catheter such that at least a portion of theballoon is in a coronary artery or in a carotid artery.

In yet another aspect, the invention is directed to a method of reducingatrial fibrillation. The method includes inserting a catheter at leastpartially into the heart, the catheter having a balloon, a portion ofthe balloon located in the left atrium and a portion of the balloonlocated in a pulmonary vein. The balloon is then inflated with aperfluorocarbon such that an exterior surface of the balloon is incontact with at least a partial circumference of the portion of thepulmonary vein adjacent the left atrium, the perfluorocarbon having atemperature in the range of about −10° C. to −50° C.

Variations of the method may include one or more of the following. Theballoon may have a working region having a length of between about 5 mmand 10 mm. The method may further include inserting a wire having aneedle point from the femoral vein into the right atrium and forming ahole using the needle point in the interatrial septum between the rightatrium and the left atrium. A guide catheter may then be inserted intothe right atrium. A guide wire may further be inserted through the guidecatheter into the right atrium and further into a pulmonary vein. Thecatheter may then be disposed over the guidewire into a volume definedby the joint of the right atrium and the pulmonary vein.

Advantages of the invention may include one or more of the following.The invention inhibits or reduces the rate of restenosis following aballoon angioplasty or any other type of vascular intervention. At leastthe following portions of the vascular anatomy can benefit from such aprocedure: the abdominal aorta (following a stent or graft placement),the coronary arteries (following PTCA or rotational artherectomy), thecarotid arteries (following an angioplasty or stent placement), as wellas the larger peripheral arteries.

When the invention is used to treat atrial fibrillation, the followingadvantages inure. The cooled tissue is adherent to the heat transferelement, increasing the heat transfer effected. Since very coldtemperatures may be employed, the temperature gradient can be quitelarge, increasing the heat transfer rate.

In both embodiments, heat transfer does not occur primarily or at all byvaporization of a liquid, thus eliminating a potential cause of bubblesin the body. Nor does cooling occur primarily or at all by a pressurechange across a restriction or orifice, this simplifying the structureof the device. Thrombus formation and charring, associated with priortechniques, are minimized or eliminated.

Additional advantages will be apparent from the description thatfollows, including the drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a side schematic view of a catheter according to a firstembodiment of the invention.

FIG. 1B shows a cross-sectional view of the catheter of FIG. 1A, asindicated by lines 1B-1B in FIG. 1A.

FIG. 2A shows a side schematic view of a catheter according to a secondembodiment of the invention.

FIG. 2B shows a cross-sectional view of the catheter of FIG. 2A, asindicated by lines 2B-2B in FIG. 2A.

DETAILED DESCRIPTION

Referring to FIG. 1A, a catheter 100 is shown according to a firstembodiment of the invention. The catheter 100 has a proximal end 130 anda distal end 114. Of course, this figure is not necessarily to scale andin general use the proximal end 130 is far upstream of the featuresshown in FIG. 1A.

The catheter 100 may be used within a guide catheter 102, and generallyincludes an outer tube 103, a dual balloon 134, and an inner tube 122.These parts will be discussed in turn.

The guide catheter 102 provides a tool to dispose the catheter 100adjacent the desired location for, e.g., angioplasty or reduction ofatrial fibrillation. Typical guide catheter diameters may be about 6french to 9 french, and the same may be made of polyether blockamide,polyamides, polyurethanes, and other similar materials. The distal endof the guide catheter is generally adjacent the proximal end of the dualballoon 134, and further is generally adjacent the distal end of theouter tube 103.

The ability to place the guide catheter is a significant factor in thesize of the device. For example, to perform angioplasty in the carotidarteries, which have an inner diameter of about 4 to 6 mm, a suitablysized guide catheter must be used. This restricts the size of thecatheter 100 that may be disposed within the guide catheter. A typicaldiameter of the catheter 100 may then be about 7 french or less or about65 to 91 mils. In a second embodiment described below, a catheter foruse in the coronary arteries is described. Of course, which catheter isused in which artery is a matter to be determined by the physician,taking into account such factors as the size of the individual patient'saffected arteries, etc.

The outer tube 103 houses the catheter 100 while the latter traversesthe length of the guide catheter 102. The outer tube 103 may have adiameter of about 4 french to 7 french, and the same may be made ofpolyether blockamide, poly-butylene terephalate, polyurethane,polyamide, polyacetal polysulfone, polyethylene, ethylenetetrafluoroethylene, and other similar materials.

The distal end of the outer tube 103 adjoins the proximal end of thedual balloon 134. The outer tube 103 provides a convenient location formounting a proximal end of an outer balloon 104 within the dual balloon134, and further may provide an inlet 128 for providing a fluid such asa liquid to a first interior volume 106 between the dual balloons. Insome cases, an inlet 128 per se may not be necessary: the fluid, whichmay also be a sub-atmospheric level of gas or air, may be providedduring manufacture in the first interior volume 106. In this case, theproximal and distal ends of the first interior volume may be sealedduring manufacture. The inlet 128 may be at least partially defined bythe annular volume between the interior of the outer tube 103 and theexterior of the inner tube 122.

The dual balloon 134 includes an outer balloon 104 and an inner balloon108. Between the two is the first interior volume 106. The outer balloon104 may be inflated by inflating the interior volume 106. The innerballoon 108 has a second interior volume 110 associated with the same.The inner balloon 108 may be inflated by inflating the second interiorvolume 110.

To avoid the occurrence of bubbles in the bloodstream, both the innerballoon 108 and the outer balloon 104 may be inflated usingbiocompatible liquids, such as Galden® fluid, perfluorocarbon-basedliquids, or various contrast agents. There is no need that the fluidinflating one of the interior volumes be the same fluid as thatinflating the other. Additional details on these fluids are describedbelow.

In the case of the first interior volume 106, this fluid may be, e.g.,stationary or static: in other words, it need not be circulated. In thecase of the second interior volume 110, this fluid would in general becirculated by an external chiller (not shown). The chiller may be, e.g.,a gear pump, peristaltic pump, etc. It may be preferable to use a gearpump over a peristaltic pump as the attainable pressure of the former isgenerally greater than that of the latter. Moreover, gear pumps have theadvantageous property of being linear, i.e., their output varies indirection proportion with their revolutions per minute. Two types ofgear pumps which may be employed include radial spur gear pumps andhelical tooth gear pumps. Of these, the helical tooth gear pump may bemore preferable as the same has been associated with higher pressuresand a more constant output. The ability to achieve high pressures may beimportant as the cooling fluid is required to pass through a fairlynarrow, e.g., five to seven french, catheter at a certain rate. For thesame reason, the viscosity of the fluid, at the low temperatures, shouldbe appropriately low. For example, an appropriate type of fluid may beGalden® fluid, and in particular Galden®g fluid item number “HT-55”,available from Ausimont Inc. of Thorofare, N.J. At −55° C., this fluidhas a viscosity of 2.1 centiStokes. At −70° C., this fluid has aviscosity of 3.8 centiStokes. It is believed that fluids with suchviscosities at these temperatures would be appropriate for use.

The so-called “cones” of the balloons 108 and 104, indicated generallyby reference numeral 132, may be made somewhat thicker than theremainder of the balloon sections. In this way, the heat transferefficiency in these sections is significantly less than over theremainder of the balloon sections, this “remainder” effectively defininga “working region” of the balloon. In this way, the cooling or“cryoplasty” may be efficiently localized to the affected area ratherthan spread over the length of the balloon.

The inner tube 122 is disposed within the interior of the dual balloon134 and within the interior of the guide catheter 102. The inner tube122 includes a supply lumen 120, a return lumen 118, and a guidewirelumen 116. The guidewire lumen 116 may have sizes of, e.g., 17 or 21mils inner diameter, in order to accommodate current standard sizedguidewires, such as those having an outer diameter of 14 mils. Thisstructure may be preferable to a coaxial structure, as the pressure dropencountered may be substantially less. In use, the supply lumen 120 maybe used to supply a circulating liquid to the second interior volume110. The return lumen 118 may be used to exhaust the circulating liquidfrom the second interior volume to the external chiller. As may be seenfrom FIG. 1A, both lumens 118 and 120 may terminate prior to the distalend 114 of the catheter 100. The lumen arrangement may be seen moreclearly in FIG. 1B.

A set of radio opaque marker bands 112 may be disposed on the inner tube122 at locations substantially adjacent the cones 132 to define acentral portion of the “working region” of the balloons 104 and 108.This working region is where the “cryoplasty” procedures described belowmay substantially occur.

As noted above, the proximal portion of the outer balloon 104 is mountedon the outer tube 103 at its distal end. The distal end of the outerballoon 104 is secured to the distal end of the catheter 100 and alongthe inner tube 122. In contrast, both the proximal and distal ends ofthe inner balloon 108 may be secured to the inner tube 122 to create asealed second interior volume 110.

At least two skives 124 and 126 may be defined by the inner tube 122 andemployed to allow the working fluid to exit into the second interiorvolume 110 and to exhaust the same from the second interior volume 10.As shown in the figure, the skive 124 is in fluid communication with thelumen 120 and the skive 126 is in fluid communication with the lumen118. Here, “fluid communication” refers to a relationship between twovessels where a fluid pressure may cause a net amount of fluid to flowfrom one vessel to the other.

The skives may be formed by known techniques. A suitable size for theskives may be from about 50 mils to 125 mils.

A plurality of tabs 119 may be employed to roughly or substantiallycenter the inner tube 122 within the catheter 100. These tabs may havethe shape shown, the shape of rectangular or triangular solids, or othersuch shapes so long as the flow of working fluid is not unduly impeded.In this specification, the phrase “the flow of working fluid is notunduly impeded” is essentially equated to the phrase “substantiallycenter”. The tabs 119 may be made of polyether blockamide, poly-butyleneterephalate, polyurethane, polyamide, polyacetal polysulfone,polyethylene, ethylene tetrafluoroethylene, and other similar materials,and may have general dimensions of from about 3 mils to 10 mils inheight, and by about 10 mils to 20 mils in width.

In a method of use, the guide catheter 102 may be inserted into anaffected artery or vein such that the distal tip of the guide catheteris just proximal to an affected area such as a calcified area or lesion.Of course, it is noted that typical lesions do not occur in the venoussystem, but only in the arterial.

This step provides a coarse estimate of proper positioning, and mayinclude the use of fluoroscopy. The guide catheter may be placed using aguide wire (not shown). Both the guide catheter and guide wire mayalready be in place as it may be presumed a balloon angioplasty or stentplacement has previously been performed.

The catheter 100 may then be inserted over the guide wire via the lumen116 and through the guide catheter 102. In general, both a guide wireand a guide catheter are not strictly necessary—one or the other mayoften suffice. During insertion, the dual balloon 134 may be uninflatedto maintain a minimum profile. In fact, a slight vacuum may be drawn tofurther decrease the size of the dual balloon 134 so long as thestructural integrity of the dual balloon 134 is not thereby compromised.

When the catheter 100 is distal of the distal tip of the guide catheter102, a fine positioning step may occur by way of the radio opaque markerbands 112. Using fluoroscopy, the location of the radio opaque markerbands 112 can be identified in relation to the location of the lesion.In particular, the catheter may be advantageously placed at the locationof the lesion and further such that the lesion is between the two markerbands. In this way, the working region of the balloon 134 willsubstantially overlap the affected area, i.e., the area of the lesion.

Once placed, a biocompatible heat transfer fluid, which may also containcontrast media, may be infused into the first interior volume 106through the inlet 128. While the use of contrast media is not required,its use may allow early detection of a break in the balloon 104 becausethe contrast media may be seen via fluoroscopy to flow throughout thepatient's vasculature. Subsequently a biocompatible cooling fluid may becirculated through the supply lumen 120 and the return lumen 118. Beforeor during the procedure, the temperature of the biocompatible coolingfluid may be lowered to a therapeutic temperature, e.g., between −40° C.and −60° C., although the exact temperature required depends on thenature of the affected area. The fluid exits the supply lumen 120through the skive 124 and returns to the chiller through the skive 126and via the return lumen 118. It is understood that the respective skivefunctions may also be reversed without departing from the scope of theinvention.

The biocompatible cooling fluid in the second interior volume 110 chillsthe biocompatible heat transfer fluid within the first interior volume106 to a therapeutic temperature of, e.g., between about −25° C. and−50° C. The chilled heat transfer fluid transfers thermal energy throughthe wall of the balloon 104 and into the adjacent intimal vasculartissue for an appropriate therapeutic length of time. This time may be,e.g., about ½ to 4 minutes.

Upon completion of the therapy, the circulation of the biocompatiblecooling fluid may cease. The heat transfer fluid within the firstinterior volume 106 may be withdrawn though the inlet 128. The balloons104 and 108 may be collapsed by pulling a soft vacuum through any or allof the lumens 124, 126, and 128. Following collapse, the catheter 100may be withdrawn from the treatment site and from the patient throughthe guide catheter 102.

To inhibit restenosis, the following therapeutic guidelines may besuggested:

Minimum Average Maximum Temperature of heat −20° C. −55° C. −110° C.transfer fluid Temperature 0° C. to −10° C. −20° C. to −50° C. toachieved at intimal −30° C. −100° C. wall Depth of penetration 10ths ofmm 1 mm 3 mm of intema/media Length of time fluid 30 seconds 1-2 min 4-5min is circulating

Substantially the same catheter may be used to treat atrialfibrillation. In this method, the catheter is inflated as above once itis in location. The location chosen for treatment of atrial fibrillationis such that the working region spans a portion of the left atrium and aportion of the affected pulmonary vein. Thus, in this embodiment, theworking region of the catheter may have a length of about 5 mm to 30 mm.The affected pulmonary vein, of the four possible pulmonary veins, whichenter the left atrium, may be determined by electrophysiology studies.

To maneuver the catheter into this location, a catheter with a needlepoint may first be inserted at the femoral vein and routed up to theright atrium. The needle of the catheter may then be poked through theinteratrial septum and into the left atrium. The catheter may then beremoved if desired and a guide catheter disposed in the same location. Aguide wire may be used through the guide catheter and may be maneuveredat least partially into the pulmonary vein. Finally, a catheter such asthe catheter 100 may be placed in the volume defining the intersectionof the pulmonary vein and the left atrium.

A method of use similar to that disclosed above is then employed to coolat least a portion of, and preferably all of, the circumferentialtissue. The coldness of the balloon assists in the adherence of thecircumferential tissue to the balloon, this feature serving to increasethe overall heat transfer rate.

The catheter 100 above may be particularly useful for procedures in thecarotid arteries by virtue of its size. For use in the coronaryarteries, which are typically much smaller than the carotid artery, aneven smaller catheter may be desired.

Referring to FIG. 2A, a catheter 200 is shown according to a secondembodiment of the invention. This embodiment may be particularly usefulfor use in the coronary arteries because the dimensions of the catheter200 may be considerably smaller than the dimensions of the catheter 100.However, in several ways the catheter 200 is similar to theabove-described catheter 100. In particular, the catheter 200 has aproximal end 230 and a distal end 214 and may be used within a guidecatheter 202. The catheter 200 includes an outer tube 203, a dualballoon 234, and an inner tube 222.

The ability to place the guide catheter is a significant factor in thesize of the device. For example, to perform angioplasty in the coronaryarteries, which have an inner diameter of about 1½ to 4½ mm, a suitablysized guide catheter may be used. This then restricts the size of thecatheter 200 which may be disposed within the guide catheter. A typicaldiameter of the catheter 200 may then be about 3 french or less or about35-39 mils. The same may be placed in the femoral artery in order to beable to track to the coronary arteries in a known manner.

Analogous to these features in the catheter 100, the outer tube 203houses the catheter 200 and may have an outside diameter of about 5french to 7 french, and the same may be made of similar materials. Thedistal end of the outer tube 203 adjoins the proximal end of the dualballoon 234. The outer tube 203 provides a mounting location for anouter balloon 204, and further provides an inlet 228 for providing afluid such as a liquid to a first interior volume 206 between the dualballoons. As noted in connection with catheter 100, an inlet 228 per semay not be necessary: the fluid, which may also be a sub-atmosphericlevel of air, may be provided in the first interior volume 206. Also asabove, the proximal and distal ends of the volume may be sealed duringmanufacture. The inlet 228 may be at least partially defined by theannular volume between the interior of the outer tube 203 and theexterior of the inner tube 222.

The dual balloon 234 includes an outer balloon 204 and an inner balloon208. These balloons are basically similar to balloons 104 and 108described above, but may be made even smaller for use in the smallercoronary arteries.

The same types of fluids may be used as in the catheter 100.

The inner tube 222 is disposed within the interior of the dual balloon234 and within the interior of the guide catheter 202. The inner tube222 includes a supply lumen 220 and a return lumen 218.

A set of radio opaque marker bands 212 may be disposed on the inner tube222 for the same reasons disclosed above in connection with the markerbands 112.

As noted above, the proximal portion of the outer balloon 204 is mountedon the outer tube 203 at its distal end. The distal end of the outerballoon 204 is secured to the distal end of the catheter 200 and alongthe inner tube 222. In contrast, both the proximal and distal ends ofthe inner balloon 208 may be secured to the inner tube 222 to create asealed second interior volume 210.

At least two skives 224 and 226 may be defined by the inner tube 222 andemployed to allow the working fluid to exit into the second interiorvolume 210 and to exhaust the same from the second interior volume 210.

A plurality of tabs 219 may be employed to roughly or substantiallycenter the inner tube 222 within the catheter 200 as in catheter 100.These tabs may have the same general geometry and design as tabs 119. Ofcourse, they may also be appropriately smaller to accommodate thesmaller dimensions of this coronary artery design.

The tabs 119 and 219 are particularly important in the catheters 100 and200, respectively, because the tabs lessen the pressure drop encounteredby the fluid. Contact by the inner tube of the outer tube may also beassociated with an undesired heat transfer prior to the working fluidreaching the working region, thereby deleteriously increasing thetemperature of the working fluid at the working region.

The method of use of the catheter 200 is generally the same as for thecatheter 100. Known techniques may be employed to place the catheter 200into an affected coronary artery. For the catheter 200, an externalguidewire may be used with appropriate attachments to the catheter.

The invention has been described above with respect to particularembodiments. It will be clear to one of skill in the art that numerousvariations may be made from the above embodiments with departing fromthe spirit and scope of the invention. For example, the invention may becombined with stent therapies or other such procedures. The dual balloondisclosed may be used after angioplasty or may be an angioplasty balloonitself. Furthermore, while the invention has occasionally been termedherein a “cryoplasty catheter”, such a term is for identificationpurposes only and should not be viewed as limiting of the invention.Fluids that may be used as heat transfer fluids includeperfluorocarbon-based liquids, i.e., halogenated hydrocarbons with anether bond, such as FC 72. Other materials that may be used includeCFCs, Freon®, or chemicals that when placed together cause anendothermic reaction. Preferably, low viscosity materials are used asthese result generally in a lessened pressure drop. The balloons may bemade, e.g., of Pebax, PET/PEN, PE, PA 11/12, PU, or other suchmaterials. Either or both of the dual balloons may be doped to improvetheir thermal conductivities. The shaft of inner tube 122 may be made ofPebax, PBT, PI/PEI, PU, PA 11/12, SI, or other such materials. Othervariations will be clear to one of skill in the art, thus the inventionis limited only by the claims appended hereto.

1. A method of reducing restenosis after angioplasty in a blood vessel,comprising: inserting a catheter into a blood vessel, the catheterhaving a balloon; inflating the balloon with a perfluorocarbon such thatan exterior surface of the balloon is in contact with at least a partialinner perimeter of the blood vessel, the perfluorocarbon having atemperature in the range of about −10° C. to −50° C.
 2. The method ofclaim 1, further comprising the step of disposing the catheter at adesired location using at least one marker band.
 3. The method of claim1, further comprising flowing the perfluorocarbon into the balloon usinga supply lumen and exhausting the perfluorocarbon from the balloon usinga return lumen.
 4. The method of claim 1, wherein the balloon is a dualballoon, and further comprising providing a heat transfer fluid in thevolume between the dual balloons.
 5. The method of claim 4, wherein theheat transfer fluid includes a contrast media fluid.
 6. The method ofclaim 1, further comprising disposing the catheter such that at least aportion of the balloon is in a coronary artery.
 7. The method of claim1, further comprising disposing the catheter such that at least aportion of the balloon is in a carotid artery.